This invention relates to a process for producing a polyurethane foam having a high abrasion index and high resistance to discoloration and shrinkage, and preferably having a high density, which is particularly useful in the outsoles of cold weather boots. More particularly, the invention relates to predominantly open cell, water blown, polyurethane foams made from a polyether diol and a cycloaliphatic diisocyanate and having good low temperature properties.
Polyurethane foams of the prior art have been notoriously lacking in abrasion resistance. Many of them have been characterized by having a tendency to discolor badly, as by turning yellow, when exposed to ultraviolet light for prolonged periods of time. Many of them have also had a tendency to shrink considerably during molding thereof after having been formed into a desired shape, as by directly molding on a boot or shoe as an outsole. These deficiencies in the prior art polyurethane foams have militated against their utilization in the manufacture of boots for military use in low temperature environments where retention of good camouflage against a snow-covered background is very important along with high resistance to abrasion and good flexibility and strength at low temperatures.
It is, therefore, an object of the present invention to provide a process for producing polyurethane foam having high resistance to abrasion, discoloration, and shrinkage and characterized by good flexibility and strength at low temperatures.
A further object is to provide predominantly open cell, water blown, polyurethane foams made from a polyether diol and a cycloaliphatic diisocyanate having high resistance to abrasion, discoloration and shrinkage and possessing high densities and good low temperature properties.
Other objects and advantages will appear from the following description, and the novel features will be particularly pointed out in connection with the appended claims.